I just watched a youtube video where the guy drilled two holes and removed the small space between, got it into a near perfect oval tic-tac shape. He also got a little black rubber thingy (<--tech talk I know) to help prevent water from getting in. But I think his frame is a cheap aluminum one. I imagine drilling a chromag will be harder.
https://www.youtube.com/watch?v=BGq09CWfJxA
This video looks interesting. He puts the hole in the BACK of the seat tube. Odd.
What do you guys put on the bare metal after such a modification? Some clear paint?
I’ve only drilled aluminum so I put nothing on the hole.
Posted by: BC_Nuggets
What do you guys put on the bare metal after such a modification? Some clear paint?
I have a bottle of clear nail polish for mod tidying.
Cable entry at the back of the seat tube is actually ideal IMO if your cables run under the bb shell
Posted by: Vikb
First ride in 6 weeks after breaking my toe. Shorts/t-shirt and dusty trails. My calendar says it's October, but it sure doesn't feel like it! Now to build fitness and avoid further injuries.
Jealous of your injury recovery I readily admit.
Posted by: Endurimil
Jealous of your injury recovery I readily admit.
I flipped back and forth between feeling sorry for myself not being able to much sporty stuff the last 6 weeks and appreciating, that while it was annoying, it was a minor injury in the great scheme of things.
Did another local XC hardtail ride this morning. Nice to be riding with my GF instead of having her tell me what the trails are like after she goes riding. One downside to having most of my social interactions setup around sporty activities is that when I'm injured I feel pretty unplugged. Terrible timing as I missed 4 sweet trips/events with amazing weather, but $hit happens. I'm just happy to be rolling on dirt again.
Posted by: BC_Nuggets
Posted by: [email protected]
Good thing that these days we have an abundance of choice in reliable droppers of all lengths to cover all possible combinations of body shape, bike geo and riding style! ;-)
Except if you don't have internal routing for dropper. Where's the affordable wireless technology?
There isn't a dropper for no internal routing. Weird....
Posted by: BC_Nuggets
I also want to shorten my seat tube (can maybe do between half to full inch) but might not need to since internal posts have lower stack height than external.
The stealth dropper drilling is as tashi said. I do two holes, just about touching - and finish up by either wiggling the bit to connect or filing/dremel tooling them into one oval.
Drill bit size is ~5mm (if you have metric bits) or so. A 1/4” bit is closer to 6mm and that works too. The tip to centre punch first is a good one especially if it’s steel so the bit doesn’t walk.
I avoid drilling within 1” of a weld but I’m not sure if that’s necessary. I could be wrong but it seems like the metal is more brittle there from the heat during the weld.
Cutting a seat tube is much the same thing. Measure the length of the slot in the seat tube to start. If you deviate too much from that length the seat tube can have a hard time clamping the seat post. Drill a hole at the end and then use an angle grinder to connect the slot to the hole. I cut my last aluminum one with a pipe cutter and faced it up with a 60 grit flap disc on a grinder but a file could do the same thing. Last steel frame I cut I used a sawzall with a hacksaw bit.
Parts store touch up paint (in a shade close to yours) covers up the exposed edges on a steel frame nicely
Good luck! Just go for it. Plumbers and electricians cut tubing like this for pipes or conduit literally all day so the tools are easily found at any hardware store if you’re missing anything.
I've drilled holes for droppers in both alum' and steel.
4mm bit straight in and GENTLY worked vertically back and forth to ovalize the hole and it takes a standard gear cable housing perfectly. You'll need to put the housing end cap on from the top of the seat tube cos the hole is so snug.
Be brave. Do it!
Posted by: Endurimil
Posted by: BC_Nuggets
Posted by: [email protected]
Good thing that these days we have an abundance of choice in reliable droppers of all lengths to cover all possible combinations of body shape, bike geo and riding style! ;-)
Except if you don't have internal routing for dropper. Where's the affordable wireless technology?
There isn't a dropper for no internal routing. Weird....
LOL. Yeah there's still some choices out there. Not a lot though. Still might drill a hole to expand my options. Thanks everyone!
I've been out enjoying the unseasonably warm/sunny/dry conditions making up for lost riding time. Trails are dry and dusty in a way my brain can't correlate with it being mid-October. I managed to finally get a flat after so long I can't recall when the last one happened, but it was at least a couple years ago now. I landed on something sharp off a small drop and put a hole in the tire mid-tread. Small enough it didn't want to eat some bacon. Big enough it didn't want to seal right away. I put something like 8 psi in the tire and rode home out of the trails on a soft tire + Tannus insert with no issues. Since I had to ride home from the trails I put a bit more air into the tire for the pavement and rolled home.
I've got some fresh winter rubber for the bike I'll put on today. I'll repair the old tire with a patch on the inside and keep it as a back up.
Although getting a flat is slightly annoying it's great that I can ride so much on current tire/insert/rim tech with exceedingly few flats and no rim damage. Particularly on the rear of a hardtail.
Posted by: Vikb
I've been out enjoying the unseasonably warm/sunny/dry conditions making up for lost riding time. Trails are dry and dusty in a way my brain can't correlate with it being mid-October.
Yeah! Is it just me or is the dirt more slippery and the roots more grippy than they should be? ;)
If you’re drilling a seat tube I’d consider:
- the lowest stress / strongest place to drill is the BB shell itself, so if you’re running a configuration where you can route around the bb and spindle (zero contact or you’ll wear the spindle, a centre sleeve to protect is probably a must), do it that way.
- mock up the bend. If it’s in a bad place you won’t be able to undrill.
- don’t drill opposite bottle cage bosses or anything else applying stress to frame.
- centre punch is a great start.
- low speed drill. A pilot hole with a 2mm will be a big help.
- 20-30mm from bottom of tube should be enough to avoid compromising but also still be in the thicker butt rather than the thin central part of the tube. Depending on your frame manufacturer they might actually have the tube spec which would be helpful. Knowing where the butts are is really helpful, I recommend it.
- if it’s steel, use some sugru / kintsuglue / silicone sealant once installed so you can keep water out of the tube. Some nail polish or paint is a good idea.
- if it’s not steel or Ti then it’s probably going to shorten it’s life span drilling it.
- AXS 🫤
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